Hints of the third sound of Tartini - combination sounds

The third sound of Tartini , also known as the "combination sound", is the sound generated by the combination of 2 notes, whose frequency corresponds to the difference in the frequencies of the 2 generating notes; in this example F2 is obtained from the combination of F4 and C4, and its frequency is the difference between those 2 notes (F4 349Hz - C4 262Hz = F2 87Hz), while F3 (175Hz) is the second harmonic of the new note F2 (87Hz).